1. Field of the Invention
The present invention relates to a method and apparatus for supporting a tubular within a bore, and in particular, but not exclusively, to a method and apparatus for supporting liner tubing within a cased subterranean bore.
2. Description of the Related Art
In the oil and gas exploration and production industry, subterranean bores are drilled from surface to intercept hydrocarbon bearing formations, which often requires bore reaches of as much as 6000 to 10000 metres, for example. In conventional drilling operations, a bore is drilled to a depth of around, for example, 600 metres, when the drill bit and associated drill string is then removed and a string of casing run in and cemented in place to support and seal the bore. Drilling is then recommenced for a further 600 metres, for example, following which a further string of casing is required to support the bore. However, in this case the casing is normally tied back to, and supported from the surface by the wellhead. This procedure is repeated until the bore reaches or nears the required total depth. Once the final drilling stage is completed the drilling string is pulled out of the hole and the final bore section is supported by a liner casing string which does not extend back to the wellhead, but instead terminates downhole and is supported by the previous full string of casing. Thus, special liner hangers are required to allow the liner string to be coupled to and supported by the previous casing string.
Conventional liner hangers may be initially coupled to the liner string which is run in hole to the required depth using a setting tool string, and the liner hanger is then set in place within the bore. Typical liner hangers are set in place by mechanical activation of slips or the like, which are brought into engagement with the wall of the bore, thus providing support for the liner.
It is among the objects of embodiments of the present invention to provide an improved method and apparatus for providing hanging support for a liner.